External halyard revolving truck is made from cast aluminum with a cast nylon sheave. Includes a cast slip over cap and is secured to the shaft. by three 1/4 in. stainless steel set screws. The truck body rotates on 26 stainless steel ball bearings on cast races. The top of the assembly is tapped 1/2 in. to accept an ornament/finial. Maximum recommended halyard diameter is 5/16 in.